The present disclosure relates to a vehicle controller that performs travel control on a vehicle based on a plurality of travel modes planned for the vehicle. The vehicle uses an internal combustion engine and a motor as drive sources.
A plug-in hybrid vehicle is well known in the art as a vehicle that uses an internal combustion engine and a motor as drive sources. Such a vehicle travels in modes including a first mode, which serves as a charge depleting (CD) mode and consumes electric power of the battery, and a second mode, which serves as a charge sustaining (CS) mode and sustains the amount of power stored in the battery. For example, the CD mode gives priority to EV traveling, in which the motor drives the vehicle while the internal combustion engine is stopped. Thus, use of the internal combustion engine is limited or prohibited. The CS mode gives priority to HV traveling, in which the internal combustion engine and the motor are both used to sustain the storage power amount of the battery.
Japanese Laid-Open Patent Publication No. 2009-12605 describes a vehicle controller that performs travel control on the vehicle by calculating a route, which includes a plurality of zones from an originating point to a destination, and planning which one of the first mode and the second mode is to be assigned to each zone of the calculated route as the travel mode for the vehicle.
In the device described in Japanese Laid-Open Patent Publication No. 2009-12605, the second mode is applied to the zone that has the highest average vehicle speed in the route, and the first mode is applied to the remaining zones. Then, the device estimates the state of charge of the battery that would be obtained when the vehicle travels in the applied mode from the current location and reaches the destination. When the estimated value is smaller than the lower limit, which corresponds to a depletion state of the battery, the device changes the mode of the zone having the second highest average vehicle speed from the first mode to the second mode and estimates the battery state of charge that would be obtained when the vehicle reaches the destination.
The device sequentially changes the mode of the zones having higher average vehicle speed from the first mode to the second mode so that the estimated value of the battery state of charge is approximate to and above the lower limit at the destination. When the estimated value of the battery state of charge remains above the lower limit when the vehicle reaches the destination, the device plans the travel modes for the vehicle using the currently applied mode of each zone.